1. Field of the Invention
The present invention relates to a power switch on/off mechanism of a plug-in unit driven by an insertion/ejection device in a PCB (Printed Circuit Board), and particularly, to an improved power switch on/off mechanism of a plug-in unit driven by an insertion/ejection device in a PCB wherein a power switch installed in a plug-in unit can be activated in cooperation with a PCB insertion/ejection device which is used for inserting/ejection a plug-in unit into/from a sub-rack assembly.
2. Description of the Conventional Art
As the construction of the electronic system becomes complicated and high-integrated, a plurality of accurate electronic elements are mounted in a circuit pack. Therefore, the input/output (I/O) per PCB, namely, the number of connector pins reaches about 1,000.
Therefore, when inserting/ejecting a plug-in unit (a circuit pack) into/from a sub-rack of a system, when the connector pins of the plug-in unit are connected with the connector pins of a backplane installed in a sub-rack assembly and are separated therefrom, the connector pins do not concurrently contact therewith, so that the power is supplied to the plug-in unit under an unstable and inaccurate connection condition therebetween, thus causing a malfunction and damage of the circuit system.
In order to prevent the above-described problems, an on/off mechanism of a plug-in unit power switch is provided in an insertion/ejection device which is used for inserting/ejecting a plug-in unit into/from a sub-rack of the system and a printed circuit board (PCB), so that the power is supplied to the circuit system in such a manner that the connection pins of the plug-in unit and the connector pins of the backplane of the sub-rack assembly are accurately connected, and the supply of the power to the circuit system is stopped before the connector pins of the plug-in unit and the connector pins of the backplane of the sub-rack assembly are separated from each other, thus increasing the reliability of the system.
FIGS. 9A and 9B illustrate an operational sequence whereby a conventional circuit pack power on/off mechanism of an insertion/ejection device activates a power switch installed in a printed circuit board (PCB).
As shown therein, in the conventional circuit pack power on/off mechanism, a plug-in unit power switch 540 is installed in a printed circuit board (PCB) 550. A power switch lever 530 is installed in one end of the power switch 540. A power switch on/off protrusion 560 is integrated within handle 510 wherein the power switch lever 530 is inserted into the interior of a jaw 520 for an on/off operation of the power switch lever 530.
As shown in FIG. 9A, in order to install the plug-in unit into the sub-rack assembly, the handle 510 is upwardly moved in the direction indicated by the arrow in the drawings, the plug-in unit is forwardly moved along a guide rail 570. Thereafter, the handle 510 is further moved, the connector pins of the plug-in unit and the connection pins of the backplane are not accurately connected. In addition, as shown in FIG. 9B, the power switch on/off protrusion 560 of the handle 510 is inserted into the power switch lever 530 inside the jaw 520, so that the lever 530 is set at an on-state.
However, in the conventional on/off mechanism of the plug-in unit power switch, since the power switch lever 530 is converted into an on-state in a state that the connection pins of the plug-in unit and the connector pins of the backplane are nearly connected, the power switch on/off protrusion 560 is integral with the handle 510, and the handle 510 and the power switch on/off protrusion 560 are integrally moved, when inserting/ejecting the plug-in unit, the connection pins of the plug-in unit and the connector pins of the backplane may be separated from each other before the power switch lever 530 is fully converted into an off state.
In addition, when inserting/ejecting the plug-in unit having the power switch into/from the sub-rack, the on/off timing of the power switch installed in the PCB is very important. In the conventional on/off mechanism of the plug-in unit power switch, since there is no element for controlling the on/off timing of the power switch 540, it is impossible to accurately control the on/off timing of the power switch 540.
Generally, in accordance with the characteristic of the circuit pack, the on/off function of the circuit pack may be provided in the PCB of the plug-in unit. In the conventional on/off mechanism of the power switch, since the power switch on/off protrusion 560 and the handle 510 are integrally formed, and an insertion/ejection device to which the power switch on/off mechanism is adapted and another insertion/ejection device to which the same is not adapted must be separately fabricated, the fabrication cost is increased, and there are problems in maintaining the system. In addition, it is impossible to selectively use the above-described different functions.